Coffee Consumption during Pregnancy

During pregnancy and breastfeeding, caffeinated coffee is a harmful factor for the health of the fetus and the infant, respectively. In a pregnant woman, the ability to break down caffeine decreases because the metabolism takes more than twice as long to do so. As a result, the caffeine serum level in the blood of pregnant women remains elevated for a longer period of time, in contrast to non-pregnant women. In addition, caffeine can easily cross the placental barrier and affect fetal development. 70 to 140 milligrams of caffeine daily has a growth-inhibiting effect on the growing child. Women who consumed 200 mg (the equivalent of one cup of coffee) or more of caffeine per day had twice the risk of miscarriage (abortion) as women who did not consume caffeine. Caffeine levels reach about the same level in the fetus as in the mother. However, the unborn child needs a considerably longer time – about twenty times as long – as adult humans to metabolize caffeine, since certain enzymes in the liver are missing to break it down. Only after 82 hours is half of the ingested caffeine excreted.

Growth inhibitory effect

Due to the growth-inhibiting effect of the alkaloid, reduced birth weight often occurs, with such children weighing an average of 116 grams less at birth than children born to mothers who consume no more than ten milligrams of caffeine daily.

Vital Substance Deficiencies

In the placenta, blood vessels become constricted under the influence of caffeine, causing circulatory problems and preventing the fetus from receiving an adequate supply of oxygen and essential vital substances. The unborn child’s need for vitamin C, B6, calcium, magnesium and iron is greatly increased because caffeine has a diuretic effect in the mother’s body and thus many essential vital substances are flushed out with the body water. The tannins contained in coffee inhibit the absorption of iron and cause iron deficiencies in the pregnant woman’s body on the one hand and in that of the fetus on the other. Moderate to heavy caffeine consumption by the mother and the resulting loss of vital substances increase the risk of miscarriage or stillbirth threefold.

The upper limit for pregnant women is set by the EFSA (European Food Safety Authority) at 200 mg of caffeine per day.

Overview of the caffeine content of various stimulants.

Luxury food Caffeine content [mg]
Coffee (150 ml) 50-150
Espresso (50 ml) 50-150
Black tea (150 ml) 30-60
Green tea (150 ml) 40-70
Cola drink (330 ml) up to 60
Energy drink (250 ml) 80
Milk chocolate (100 g) 20
Semi-sweet chocolate (100 g) 75

For more information on “coffee consumption”, see “stimulants” in the “micronutrient medicine” superordinate topic.